Ignition timing device



l 1943- J. J. ROSE IGNITION TIMING DEVICE Filed March 5, 1942 2 Sheets-Sheet -1 L/OHN a. 20 E April 13,1943- J. J. ROSE IGNITION TIMING DEVICE Filed March 3, 1942 2 Sheets-Sheet 2 a 26 $35 38 .4 /6' 22 6) if \K\\\ JOHN Po 5 AW EN 70/? Patented Apr. 13, 1943 IGNITION TIMING DEVICE John J. Rose, Dayton, Ohio Application March 3, 1942, Serial No. 463,243

(Cl. 33-181) (Granted under the act of March 3, 1883, as

6 Claims.

amended April 30, 192

The invention described herein may be manufactured and used by or for Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a tool for so adjusting the driving connection between an engine and its ignition magneto as to bring the functions of the magneto into proper timed relation with the engine-firing positions without first having to mount the magneto on the engine as is common practice.

Inasmuch as the conventional magneto is an alternating current generator and therefore provides a uniform number of electrical impulses per rotor revolution, and since it is required that there be half as many impulses per revolution of the engine as there are engine cylinders, it follows that the gearing through which the magneto is driven by the engine must have a ratio of engine cylinders magneto impulses and since it is required that the breaker open and the firing of a cylinder take place when an electrical impulse is approaching maximum E. M. F., circumferential adjustability of the splines of the magneto shaft with respect to the rotor, or circumferential adjustability of the splines of the engine magneto driving shaft with respect to the engine, is a requisite, the former method being common practice and usually carried out by providing an externally splined sleeve on the rotor shaft which may be rotated thereon to any selected position, then secured thereto for rotation therewith.

Conventional procedure, prior to this invention, for bringing these parts into operative relation, was to rotate the crankshaft of the engine to a predetermined position for firing a given cylinder-say, for instance, 15 ahead of top dead center for that cylinderthen to position the magneto shaft so that the distributer was on that cylinder and the points of the circuit breaker just opening for that cylinder, then rotating the splined sleeve on the rotor shaft by cut and try until the splines on the sleeve would enter the splines on the engines magneto drive shaft without changing the relative rotative positions of the engine and magneto.

This procedure is necessarily slow, since it usually requires a considerable number of trials be fore the splined sleeve of the magneto shaft is secured in its proper position. It is therefore an object ofthis invention to provide a tool which Will quickly and accurately align the splines or equivalent driving means on the engine with the splines or equivalent driven means on the magneto without bringing the parts into driving relation until complete adjustment is made.

Other objects and advantages will be evident from a consideration of the following description taken together with the drawings, in which:

Fig. 1 is a perspective view of the magneto mounting pad on the engine, with the engines magneto drive shaft extending through the pad, the internal driving splines in the shaft being shown.

Fig. 2 is a perspective view of the mounting flange on the magneto with the magnetos rotor shaft extending through the flange, the sleeve having the external splines which are slidable into the internal splines of the engines magneto driving shaft being shown secured on the shaft.

Fig. 3 is an elevational view of the tool which forms the subject matter of this invention, ready to be put into operation.

Fig. 4 shows one form of externally splined magneto shaft sleeve and the internal configuration for securing it to the shaft.

Fig. 5 shows a second form of externally splined magneto shaft sleeve having a tapered inner diameter for fixing it to the tapered end of the shaft.

Fig. 6 is a vertical axial section through the tool in place on the magneto shaft sleeve, just after its withdrawal from the engines magneto driving shaft.

Like numerals refer to like parts throughout the several views.

Referring now to the drawings, a plug It] has a series of external splines l2 which are a close sliding fit in the internal splines I4 of the engines magneto drive shaft I 6. Plug I0 may have a hole extending axially therethrough for lightness.

A cylinder l8 has internal splines [9 throughout its length to closely but slidably receive the external splines I2 of the plug [0. The outside of the cylinder I8 is round, smooth, and may preferably be concentric with the plug Ill. The plug l0 may conveniently be secured in the cylinder l8 by a pin I1, about half the length of the plug being left extending, or it may beleft loose therein as desired.

Rotatable on the outside of the cylinder I8 is an annular member 20 which has two hubs 22 and 24 extending radially therefrom, the hub 22 being tapped for receiving the threaded shank 26 of the pointer 28, while the hub 24 is tapped for receiving the setscrew 3B. The pointer 28 may preferably have two plane sides 32 and 34 which converge at 36 into a substantially sharp edge. The threaded shank 26 is screwed into the tapped hub 22 to a selected depth, the depth depending on the radial distance from the shaft axis of the mounting stud holes 29 and 3| in the engine mounting pad 33 and the magneto mounting flange 35, respectively, and fixed in place by the lock nut 38. The pointer is so fixed that the sharp edge 36 is parallel to the axis of the cylinder I8, the line defined by the edge 36 being the indicating line for the mounting stud holes 29 and 3|. Any other indicating means which would have the indicating pointer at opposite ends on a line parallel with the said axis would serve a similar purpose, as for instance a rod pointed at both ends and held in axially parallel relation with the shaft axis and having the axis of the rod at the same radial distance from the axis of the engines magneto drive shaft as that of the mounting stud holes. In this case the axis of the rod would be the indicating line of the pointer mechanism. The set'screw 36 has a knurled head 40 by which it may be tightened. A shallow groove 42 surrounds the outside of the cylinder I8, and the end of the screw 36 seats in the bottom of this groove, whereby the member 20 is positioned both oircumferentially and axially on the cylinder |8.

The magneto shaft driving sleeve 44 is not a part of the tool but is retained by the magneto as part of its driving connection, once it has been properly secured thereto. Sleeve 44 of the magneto' has external splines 46 which are of the same diameter as the splines |2 on the plug ID of the tool, since both must be a close sliding fit in the internal splines M of the engines' magneto drive shaft "5. Sincethesplines I12 of the tool are a close sliding fit in the splines IQ of the cylinder l8, it follows also that the splines 46 of the magneto shaft sleeve 44 will be a close sliding fit in the splines IQ of the cylinder It.

Means mustv be provided whereby the magneto sleeve 44 may be rotated to its correct position on the magneto shaft 45 before being secured against rotation thereon. In Fig. 6 and in the detail Fig. there is shown a sleeve 44 having a tapered bore 48 which fits over a correspondingly tapered end 5|] on the magneto shaft, the sleeve being held on the tapered end by a nut 52 which is fitted'to a threaded portion 54 on the end of the shaft.

In Fig. 4 there is shown a magneto shaft sleeve 56 with a splined bore, the number of internal splines 53 being different from the number of external splines 66, the magneto shaft being required to have external splines fitted to the internal splines of the sleeves. With this type of sleeve, adjustment is made by withdrawing the sleeve from the shaft, rotating it that portion of a turn represented. by one divided by the number of splines, then restoring it.

The-sleeve 56 as shown has six internal and seventeen external splines. When it is removed from the shaft, rotated one-sixth turn and restored, a given external spline will be replaced by one which is about three and one-half degrees of rotation fro-m the position which that given spline occupied. Removing, rotating one-sixth turn, and returning the sleeve 56, therefore, is the equivalent of rotatably adjusting it in increments of about three and one-half degrees of rotation. The mounting stud holes 3| of the magneto mounting flange 35 should therefore preferably be circumferentially elongated several degrees in excess of this three and one-half degrees. Where a sleeve 44 having an internally tapered hole is used, it is not necessary to elongate the mounting stud holes 3|, since the bushing 44 may be rotatably adjusted with respect to the shaft 45 by infinitesimal increment.

The operation of the tool is as follows:

The engine is rotated to the firing position of a selected cylinder. The extending portion of the plug I0 is inserted in the end of the drive shaft 46. The setscrew 36 is loosened and the member 26 rotated until the edge 36 of the pointer 28 is at the center of one of the tapped holes 29 of the mounting pad 33, whereupon the setscrew 36 is tightened.

The tool, thus set, may now be removed from the drive shaft l6 and taken to the magneto. The nut 52 on the magneto shaft is loosened so that the sleeve 44 may turn freely on the-shaft, and the magneto is setto the sparking position of the selected cylinder, that is, with the breaker points just opening for that cylinder. The open end of the cylinder H3 is now slipped over the splined sleeve 44 on the magneto shaft, and, without allowing the magneto rotor to be shifted from its selected sparking position, the edge 36 of the pointer 28 is moved to the center of the mounting stud holes 3| of the magneto .mounting flange 35, thus rotating the sleeve 44 to the correct position in which it may be fastened by the nut 52. Obviously, plain round, instead of the elongated, mounting .stud holes 3| in the flange 35 are preferable when the sleeve 54 with the tapered hole 46 is employed.

When the sleeve 56 is being used, the nut 52 is preferably removed, and, while still retaining the magneto in the selected sparking position, the tool is put on the sleeve 56 with the pointer as close to the center of the elongated mounting stud holes 3| as possible. Shifting the cylinder l8 from one to the other of the splines 66 of the sleeve 55, moves the edge 36 of the pointer 28 about twenty one degrees for a shift from one spline to the next. When the pointer is gotten as near to the center of the elongated slot 62 as it may be by this method, the pointer maybe shifted about three and one-half degrees at a time by slipping the sleeve 56 off the magneto shaft and turning it to the next shaft spline. Inasmuch as it may not be possible to bring the edge 36 of the pointer 28 exactly to the center of a plain round mounting stud hole, the elongated slots are preferably provided as shown when used in conjunction with the magneto sleeve 56. The position of the center of the'mounting stud in the elongated slot will be indicated by the edge 36 of the pointer 26, and should preferably be marked before removal of the tool.

An important feature of the invention resides in the arrangement whereby the position of the splines of the engines magneto drive shaft, relative to a given firing position, may be sensed and set up by the tool, then by corelating the corresponding sparking position of the magneto with the tool it becomes corelated with the engine. In the entire operation it is not essential that the magneto be put on or even brought close to the engine to which it is being adjusted.

It will, of course, be obvious that the design of the specific embodiment of the invention shown in the drawings need not be too closely adhered to, as for instance, under certain circumstances, the magneto drive shaft emanating from the eninternal-combustion gine may carry an externally splined portion which may extend intoan internally splined member on the magneto, or, instead of having the rotatably adjustable splined member on the magneto, as shown, it may, in some cases, prefer ably be" carried on the engines magneto drive shaft. This and many other changes and variaants of the specific design may be included in the general concept of the invention as defined in the appended claims.

Having fully described at least one embodiment of the invention, 1 claim: 1. For use on an internal-combustion engine having magneto ignition, a tool for bringing the sparking point on the magneto for any cylinder of the engine into timed relation with the firing point on'the engine for that cylinder, said engine having an internally splined magneto driving shaft and said magneto having an externally splined hub slidable into said internally splined driving shaft and rotatable on its rotor shaft but having means to secure it against rotation thereon, and said engine and said magneto having axially parallel mounting stud holes at equal radii from the axes of the engine and magneto, said tool comprising, in combination, a cylindrical member having internal splines which are duplicative of the internal splines of the engines magneto driving shaft, a plug having external splines which are duplicative of the external splines of the rotor shaft hub, a portion of the length of said plug extending into said cylindrical member, a collar freely rotatable on the outside of the cylinone of said tapped openings, the inner end of said set-screw being seatable in a groove which extends around said cylindrical member, whereby said collar may be held against rotative and axial movement on said cylindrical member, and an aligning member supported by an integral threaded stem extending into the other tapped opening in the hub, said aligning member being in the form of a wedge bounded by two planes which converge on a line which is parallel to the magneto shaft axis and coax al with the mounting stud holes.

2. For timing a magneto ignition system on an engine, a tool for corelating the sparking point on inder of the engine with the firing point on the engine for that cylinder, said engine having an internally splined shaft and said magneto having an externally splined hub slidable into said internally splined shaft and rotatable on its rotor shaft but having means to secure it against rotation thereon, and said engine and said magneto having mounting stud holes equidistant from, and axially parallel to, their respective shafts, said tool. comprising, in combination, a member having internal splines duplicative of those in the engine's shaft, a plug having external splines duplicative of those on the rotor shaft hub, said plug having part of its length inserted in part of the length of said internally splined member, a member mounted on, and rotatable about the axis of, said internally splined member, means to lock said rotatable member in any position on said internally splined member to which it may be rotated, and a wedge-shaped aligning member mounted on said rotatable member, the wedge being defined by planes which converge in a line which is adjustable to bring it into coaxial relation with the mounting stud holes.

3. A tool for timing a magneto ignition system the magneto for any cylon, an internal-combustion engine by corelating the sparking point on the magneto for any cylinder of the engine with the firing point on the engine for that cylinder, said engine having a splined shaft and said magneto having a complementary splined shaft, the splined parts of said shafts being slidable one into the other, one of said shafts having its splined portion rotatably adjustable with respect to the shaft, and said engine and magneto having complementary mounting stud holes equidistant from, and axially parallel toytheir respective shafts, said tool comprising, in combination, a splined member having its splined portions at opposite ends in alignment with each other and slidable into the splined portions of the engine and the magneto respectively, a member mounted on, and rotatable about the axis of, the said splined member, means to lock said rotatable member in any position on said splined member to which it may be rotated, and an aligning member carried on said rotatable member having two sides converging into a line, said member being adjustable in one direction to bring said line into axially parallel relation with the shaft axes and in another direction to bring said line into coaxial relation with said mounting stud holes.

4. A tool for timing a magneto ignition system on an internal-combustion engine by corelating the sparking point on the magneto for any cylinder of the engine with the firing point on the engine for that cylinder, said engine and said magneto having shafts with complementary driving means slidable axially one into the other, one of said shafts having its driving means rotatably adjustable with respect to the shaft, and said engine and magneto having complementary mounting holes equidistant from, and axially parallel to, their respective shafts, said tool comprising, in combination, a shaft-aligning member having, at one end, driving means complementary to the driving means on the engine shaft, and, at the other end, driving means complementary to the driving means on the magneto shaft, the driving means at opposite ends of the shaftaligning member being in alignment one with the other, a member mounted on, and rotatable about the axis of, said shaft-aligning member, means to hold said member in any position to which it may be rotated, and a mounting-hole-aligning member carried on said rotatable member and having indicating points at opposite ends alignable with the centers of the mounting holes of the engine and magneto respectively, a straight line passing through both said points being parallel to the shaft axis.

5. A tool for timing a magneto ignition system on an internal-combustion engine by corelating the sparking point on the magneto for any cylinder 0f the engine with the firing point on the engine for that cylinder, said engine having a splined shaft and said magneto having a complementary splined shaft, the splined parts of said shafts being slidable one into the other, one of said shafts having its splined portion rotatably adjustable with respect to the shaft, and said engine and magneto having complementary mount-' ing stud holes equidistant from, and axially parallel to, their respective shafts, said tool comprising, in combination, a splined member having its splined portions at opposite ends in alignment with each other and slidable into the splined portions of the engine and magneto respectively, a member mounted on, and rotatable about, the axis of the said splined member, means to lock said rotatable member in any position on the splined member to which it may be rotated, and an aligning member carried on said rotatable member having two sides converging in a straight line which is parallel to the shaft axes and coaxial with the mounting stud holes.

6. A tool for timing a magneto ignition system on an internal-combustion engine by corelating the sparking point on the magneto for any cylinder of the engine with the firing point on the engine for that cylinder, said engine having a splined shaft and said magneto having a complementary splined shaft, the splined parts 0;. said shafts being slidable one into the other, one of said shafts having its splined portion rotatably adjustable with respect to the shaft, and said engine and magneto having complementary mounting stud holes equidistant from, and axially parallel to, their respective shafts, said tool comprising, in combination, a splined member having its splined portions at opposite ends in alignment with each other and slidable into the splined portions of the engine and magneto respectively, a member mounted on and rotatable about, the axis of the said splined member, means to lock said rotatable member in any position on the splined member to which it may be rotated, and an aligning member carried on said rotatable member and having indicating points at opposite ends for pointing to the centers of the mounting stud holes of the engine and magneto respectively, a straight line passing through both said points being parallel to the shaft axes.

7 JOHN J. ROSE. 

